Line feed mechanism



Jan. 26, 1954 B. F. MADSEN LINE FEED MECHANISM Filed Feb. 14, 1951 FIG.

INVENTOR BERTHEL F. MADSEN 5 W ATTORNEY Patented Jan. 26, 1954 nerthlfi iivlaiisen, Chicago, 1ll.-,= as'sig-n6r to Teletype paper-anon, Chicago, 111., a corlpbratfon pr-Delaware I .hppucafionrbruary 14,1951, serrdi'homomo a oiaim's. (C'l.1 97 -1-1'4) 1 1 The nvention relates "to page printers and more 'partictflarly "to line feed mechanisms therefor, wherebya Sheet ie step ed forwardperio'dically so that a messa e "can be typed in a plurality of line's.

The principal object of t'h'e invention is to provid'e a quie'tlyafnd efij'cientlyoperable line feed mechanism for page printers.

Another "object the"'i'rive'rit ion is to provide a line "feeding arrangement "wherein the fee-ding motion "is *sm'oeufly accelerated and -'decelerated during each line feeding opera "on.

A runner-(sweet er the'inve'rition :is to provide "a line feed mechanism comprising a gear attached to' th'e platen, and'a pair o'f raek members which are 'reeiprocated alternatively a co'rrespending pair "(if eccentric dvices under the control of a mevable pivetal support for racks, whereby simpie harmome ihdtila'h is imparted to said platen during each line feeding operation.

bthe'r obiect's and features of the invention reside in providing a positively driven line feed mechanism which ermits h'igh speed operation without overrolling or'overstepping of the platen. Moreover, the device according to the present in-'- ven'tioh does not require the aheavy load of a detent to stop'th platen 'at'th'e end (if the feedir'ig stroke. Further, the mechanism according to the invention does not require a detent or other lock to prevent play in the platen at the time the printing operation is performed, because the rack members function to hold the platen against movement during the printing operation.

A more complete understanding of the invention may be had by reference to the following description when considered in conjunction with the accompanying drawings, wherein,

Fig. 1 is a perspective representation of the line feed mechanism according to the present invention;

Fig. 2 is an elevational view of the line feed mechanism; and

Fig. 3 is a sectional view in elevation showing the line feed operating instrumentalities.

The line feed mechanism according to the present invention is adapted to be embodied in a telegraph page printer of the type disclosed in United States Patent No. 2,505,729 granted April 25, 1950, to W. J. Zenner, which disclosure is incorporated herein by reference, and made a part hereof.

Having reference to Figs. 1, 2 and 3 of the drawings herein, the line feed mechanism of the present invention comprises a gear I I fixedly reiatea to the platen 12 "of the printing rh'aehihe, an a'pairof drive 61' rack memb rs I 3 T A N 4.

Referring *to'ii rg; 3, tl1'e'line feedclutch :is I icated at I5 and may beany forin f yelfcally Operable "clutch; rdr example, it be 'of the "form s'hown in Figs. 31 ainl -32 -bf sai'd' eatent 170321505 729. w

The gear I'I rbtates 'v'vith the platen I-{l ahd' the rack members -'-I3 and I"! are a apted to be alternately -em;agesbie withthe teeth on the gear q I, with a 'slight over ap bf engageability beil-ig provided, so as tb impart Silbs'ta'ntially i iriiftirm rotativemotion t?) the gear l l ahd platen I2. Flh'e mechanism of the present mvehtibn -'obviates the j terry-movement inherent I in ip'awl and ratchet mechanisms ancliimparts to the .pl'a'ten a smoothly accelerated and deceleraited motioh, thirs 'simulating simple harmonic motion.

The rack members "I 3 "and -'I 4 are connected to eccentrics I6 "and 1-1, respectively, which are operatively related to the line feed clutch I5 ('Fi'g. 3),and power for operating said racks is derived from the main shaft 18 through said clutch. 'I h'e eccentrics thus control the reciprocato'ry motion of the rack members I3 and I4. shownin Figs. 1 and 2, the rack :members I3 and 14 are adapted to be rocked on a :movable epivot 19 comprising a roller 2| cooperable with slots 22 and 23 in said rack members I3 and I4. The friction roller 2| is carried on the vertical arm of a bell crank lever 24 pivotally mounted on a pivot stud 25 fixed to the side frame of the apparatus. The bell crank lever 24 is normally biased clockwise about pivot 25 by a spring 26 against an adjustable stop 21.

Upon rotation of the eccentrics I6 and I1, a combination of rocking motion about pivot I9 and vertically reciprocating motion is imparted to the rack members I3 and I4. When the rack members I3 and I4 are rotated clockwise about the pivot roller 2I by their respective eccentrics I6 and I 1, the teeth on the rack members I3 and I4 will engage the teeth of gear II. To permit the rack teeth to mesh with the gear teeth under pressure, the fulcrum pivot 2| is made movable so that slight counterclockwise movement is imparted to bell crank 24, thus increasing the tension of spring 26.

In the performance of the line feed operation, the line feed code signal is received by the selector mechanism, such as described in said Patent No. 2,505,729, to eifect a setting of the code bars 28 to select the line feed function control lever 29 (similar to lever 39 shown in Fig. 29 of Patent No. 2,505,729) which through its interponent 3| I 3 actuates the line feed clutch release lever (not shown), similar to lever 311 shown in Fig. of said Patent No. 2,505,729, which initiates a cycle of rotation of the line feed clutch (5, which, in turn, controls the rotation of the eccentrics i6 and I1. As shown in Fig. 1 the eccentrics l6 and 11 are arranged to actuate the racks l3 and 14 in an alternate manner, as described above.

As viewed in Fig. 2, the eccentrics l6 and I! are rotative in a counterclockwise direction. When the long radius of eccentric I6 is operative to the left of the vertical center line of the shaft I8, the rack member [3 is actuated clockwise about pivot l9 to bring the rack teeth into engagement with the gear I I. The rack member I3 is also actuated downwardly to impart counterclockwise rotation to the gear H, and hence the platen I2. Then, when the long radius of eccentric i6 is operative to the right of said vertical center line, the rack member I3 is actuated counterclockwise about pivot i9 to disengage the rack teeth from gear II. The rack member I3 is further actuated upwardly with the teeth thereon free of the gear H.

The same actions are imparted to the rack member I4 by the eccentric l1 except that they occur alternatively, thereby imparting smoothly accelerated and decelerated movement to the gear ll. As previously mentioned, the pivot i9 is yieldable, so that due to the pull of spring 25, the teeth on the rack members I3 and M are adapted to mesh with gear ll under pressure.

Although a preferred embodiment of the invention has been disclosed and described herein,

it is manifest that changes may be made in the details set forth without departing from the essentials of the invention.

What is claimed is:

1. In combination in a recorder, a platen, an instrumentality associated with said platen, a pair of drive members cooperable with said instrumentality, spring loaded means for mounting said drive members for pivotal and reciprocative movements, and a pair of eccentric means individually associated with said drive members to actuate said members, said pair of means ofiset angularly with respect to each other, whereby said drive members are engageable alternatively 4 with said instrumentality to impart rotation to said platen.

2. In combination in a recorder, a platen, a gear associated with said platen, a pair of rack members cooperable with said gear, spring loaded means for mounting said rack members for pivotal and reciprocative movements, and a pair of eccentric means individually associated with said rack members to actuate said members, said pair of means oi'r'set angularly with respect to each other, whereby said rack members are engageable alternatively with said gear to impart rotation to said platen.

3. In combination in a recorder, a platen, an instrumentality associated with said platen, a pair of drive members cooperable with said instrumentality, spring loaded means articulated to said pair of drive members in a. manner to enable pivotal and reciprocative movement of said drive members, and a pair of eccentric means individually associated with said drive members to actuate said members, said pair of means offset angularly with respect to each other, whereby said drive members are engageable alternatively with said instrumentalityv to impart rotation to said platen. V

4. In combination in a recorder, a platen, an instrumentality associated with said platen, a pair of drive members cooperable with said instrumentality, each of said members being provided with a slotted portion, yieldable fulcrum means cooperable with said slotted portions for facilitating pivotal and, reciprocative movements of said pair of drive members, and a pair of eccentric actuating means individually associated with said drive members and offset angularly with respect to each other, whereby said drive members are rendered engageable alternatively with said instrumentality to impart rotation to said platen.

BERTHZEL F. MADSEN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 7 1,861,975 Page June 7, 1932 1,944,673 Schumacher Jan. 23, 193i i Y i 

